fix: stop bandwidth measurements on terminal HTTP errors

[devandrepascoa]

• surface HTTP status codes from bandwidth connection errors and stop the top-level engine for terminal responses
• preserve retries for network failures, 408, 429, and 5xx responses
• forward loaded-latency side-engine failures through the parent bandwidth engine
• keep authorization tokens fixed for the lifetime of each engine instance

[ask-bonk]

PR adds token replacement and treats HTTP authorization failures as terminal for bandwidth requests.

Submitted 2 inline correctness findings.

Validation passed: focused unit test, TypeScript check, oxlint, and format check.

github run

[devandrepascoa]

/bonk

[ask-bonk]

Summary
Propagates bandwidth HTTP status codes through onError, stops the engine on non-OK responses, and adds HTTP-error E2E coverage.

Submitted 3 inline correctness findings.

Validation: git diff --check passed. Unit tests could not run because pnpm is unavailable in this environment.

github run